This invention relates to apparatus intended for commercial or industrial use (as distinguished from domestic use) for removing particulate matter, such as dust, from a stream of gas, such as air, by filter bag filtration.
It is known in the prior art to perform industrial filtration or dust collection in a rectangular housing or baghouse containing an array of suspended tubular filter bags. Such bags may be fabric bags with a wire cage reinforcement. The baghouse is usually divided into two plenum chambers, a lower chamber and an upper chamber. The filter bags are suspended in the lower chamber but the mouths of the bags communicate with the upper chamber. The dust-laden process air is pushed or drawn, as by a blower or fan, into the lower chamber, passes through the fabric walls into the interior of the bags and is delivered as clean air through the mouths of the bags into the upper or clean-air compartment. As the dust-laden air passes through the fabric walls into the interior of the filter bags, dust accumulates on the outer surface of the bag wall and, unless cleaned, a cake or accumulation of dust would build up on the outer wall of the bag, thereby reducing and eventually preventing the flow of air through the wall into the interior of the bag.
The prior art has provided various methods for cleaning the bags, i.e. for removing the cake of dust from the bag walls. One method is to blow pressurized air in a reverse direction through the bag walls. This is done by injecting air under pressure into the mouths of the bags to cause it to flow downwardly and outwardly through the fabric walls, thereby dislodging the dust accumulated on the outer surface of the bag walls and causing it to fall to the bottom of the lower chamber of the baghouse.
For the purpose of injecting reverse air under pressure into the mouths of the filter bags for the purpose of dislodging the dust accumulated on the outer surface of the bag, the prior art has provided a traveling cleaning head or manifold which injects pressurized air into a single row of bags at a time. Such apparatus is shown in U.S. Pat. Nos. 3,482,378 and 4,097,254. In these patents, a portion of the upper or clean-air chamber above the mouths of the filter bags is divided, by spaced vertical partition plates, into a series of compartments, one compartment for each one-half row of filter bags, and, as the traveling manifold or cleaning head travels through the clean-air compartment and comes into registry with a compartment mouth, pressurized reverse air is delivered into the mouth of that compartment, thereby injecting air into the mouths of the row of filter bags located in that particular compartment. The pressurized reverse air is shut off as the manifold moves to the next compartment, where, when the manifold is again in registry with the mouth of that compartment, the pressurized air supply is again turned on.